An image forming system of this type is configured such that, when a user instructs an information processing device to transmit secure job information, the secure job information is transmitted from the information processing device to the image forming device. The image forming device stores (holds) the transmitted secure job information in a storage unit. The secure job information contains image forming information indicative of an image and authentication information (for example, information indicative of a password) set by the user.
When the user thereafter inputs input information (for example, information indicative of a password) using an input device of the image forming device, the image forming device specifies, from among the authentication information stored in the storage unit, the authentication information that matches the input information. When the user then instructs execution of printing through the input device, the image forming device forms an image on a recording medium based on the secure job information containing the specified authentication information. That is, the image forming device executes an image forming process (printing) based on the secure job information. After completion of the image forming process, the image forming device deletes the secure job information from the storage unit.
Accordingly, printing can be performed only when the user who can input the same input information as the authentication information stored in the storage unit is close to the image forming device. Because the secure printing is performed in this fashion, the image formed on the recording medium can be prevented from being viewed by an unspecified user.
When, for example, the user instructs the transmission of secure job information but thereafter does not desire to execute the image forming process based on the secure job information, the unnecessary secure job information is not deleted from the storage unit and thus remains stored therein.
To eliminate this situation, the image forming system is further configured such that, when the user inputs input information using the input device and then instructs deletion of the secure job information, the secure job information containing the authentication information specified by the input information is deleted from the storage unit. Secure job information that has become unnecessary can thus be prevented from being kept stored in the storage unit (see, for example, Japanese Patent Application Publication No. 2004-206636-A).
The image forming system, however, suffers from the following problem: That is, in a case where a large amount of secure job information has been already stored in the storage unit to make a remaining storage area too small, new secure job information, even if transmitted, can not be stored in the storage unit. Because a user, who is unable to input the input information the same as the stored authentication information, cannot instruct the image forming device to delete the stored secure job information, the user cannot perform a new secure printing job.
On the other hand, if the image forming system is configured to permit an unspecified user to delete any stored secure job information, the stored secure job information may be deleted meaninglessly even when the storage unit can store new secure job information.